Devices are known that comprise:
a chamber provided with an injection outlet; PA1 non-return means co-operating with said outlet; PA1 a rigid piston suitable for being pushed inside the chamber towards said outlet, with lateral sealing around the piston, and suitable for returning in the opposite direction under drive from return means; PA1 means limiting the stroke of the piston in the reverse direction so that the volume of the chamber at the end of the piston return stroke corresponds to the volume of a dose to be administered; and PA1 a liquid reservoir having a capacity of several doses and communicating with the chamber via a flow rate limiter corresponding to the reference value.